Lifting jack



Jan. 17., 1956 W. C. TRAUTMAN I'AL LIFTING JACK Filed Aug. 5, 1952 2Sheets-Sheet l gill-11E- IN VEN TOR.

Jan. 17, 1956 w. c. TRAUTMAN ErAL 2,730,903

LIFTING JACK Ow Filed Aug. 5, 1952 2 Sheets-Sheet 2 United States PatentO LIFTIN G JACK Walter C. Trautman and Lyle L. Ames, Racine, Wis.,assignors to Walker Manufacturing Company of Wisconsin, Racine, Wis., acorporation of Wisconsin Application August 5, 1952, Serial No. 302,673

14 Claims. (Cl. 74--141.5)

This invention relates to lifting jacks, and more particularly to pawland ratchet type lifting jacks adapted for use as bumper jacks forvehicles and in similar applications.

It is an object to provide a novel and improved type of pawl and ratchetlifting jack, in which the holding and lifting pawls are connected by asingle coil helical spring, instead of the conventional iiat or leafspring, thus providing a construction which is cheaper to construct,more eiiicient in operation, and which increases the allowabletolerances of manufacture.

lt is another object to provide an improved lifting jack of the abovenature, which utilizes a single coil helical spring in transversebending, tension and compression, so that the coil spring can functionboth to urge the pawls toward the rack bar and to carry the pawls awayfrom the bar.

It is a further object to provide a novel and improved lifting jack ofthe above nature, having a simple lever for shifting the jack betweenits raising and lowering settings, this lever working in a slot andhaving means for preventing accidental engagement of one of the springanchor pins in said slot.

Other objects, features, and advantages of the present invention willbecome apparent from the subsequent description, taken in conjunctionwith the accompanying drawings.

ln the drawings:

Figure l is a side elevational View of a jack embodying the principlesof this invention;

Figure 2 is a fragmentary rear elevational view of the pawls, spring andsetting lever;

Figure 3 is a detailed view of the setting lever, showing the guard lip;

Figure 4 is a fragmentary side elevational view showing the operation ofthe pawls with the setting lever in raising position and the handlesocket in its lower position;

Figure 5 is a view similar to Figure 4 but with the handle socket inraised position;

Figure 6 is a view similar to Figures 4 and 5 but with the setting leverin the lowering position and the handle socket in its lower position;

Figure 7 is a view similar to Figure 6 but with the handle socket inpartially raised position; and

Figure 8 is a view similar to Figures 6 and 7 but with the handle socketin fully raised position.

The jack comprises in general a base 11 and a rack bar 12 fixed to thebase and extending upwardly therefrom. The rack bar has a plurality ofratchet teeth 13 along one edge thereof, these teeth having upwardlyfacing engaging surfaces 14 normal to the rack bar axis. The bodyportion of the jack is shown in the present embodiment as comprising twohalves, generally indicated at 15 and 16 and fabricated of pressedmetal. It wl be understood, of course, that the body of the jack couldbe constructed in other ways. Each body half 15 and 2,730,903 PatentedJan. 17, 1956 ICC " portions cooperating to form a rectangular rack barreceiving portion 17. Outwardly extending lips 18 and 19 at the upperand lower ends of the body halves are secured together and serve toconnect the halves as an integral unit. The body halves are each alsoprovided with a load engaging extension 21, these extensions also beingjoined and serving to unite the body halves.

The body halves 15 and 16 have rearwardly extending portions 22 and 23respectively in spaced. parallel relation, and between the upperportions of these relatively flat extensions is a handle socket 24supported by a pivot pin 25. The handle socket is formed intheillustrated embodiment with two spaced-apart locating portions 26 whichengage the inner surfaces of extensions 22 and 23 to prevent lateralmovement of the socket. Pivot pin 25 also pivotally supports a holdingpawl 27 which has a toe 28 at its lower end engageable with rack teeth13. Pivotally supported at 29 between portions 26 of the handle socketis a lifting pawl 3l. This lifting pawl is substantially longer thanholding pawl 27 and is shown as of somewhat arcuate shape, having a toe32 adapted to engage teeth 13. It will be noted that because of thecurved nature of pawl 31 and the rearward spacing of pin 29 from pin 25,the holding and lifting pawls are in non-interfering relationship,although they are in substantially the same plane.

Extensions 22 and 23 of the housing halves 15 and 16 substantiallyenclose holding pawl 27 and lifting pawl 31, the thickness of thesepawls being substantially less than the spacing between extensions 22and 23. Extension 22 has an upraised portion 33 which is outwardlyspaced from the longitudinal centerline of the jack, and this upraisedportion accommodates a single coil helical spring 34 which is disposedin the space between pawls 27 and 31 and extension 22. Helical spring 34is counected at one end 35 to holding pawl 27 by means of a pin 36secured to the side of the lower end of said pawl, and the other end 37of spring 34 is connected to lifting pawl 3l by means of pin 38extending from its lower portion. Spring 34 is of the type which when inits unstressed condition has open turns, so that the Ispring may beplaced under compressive load without buckling, at least for asubstantial distance until the turns are forced together. Moreover, ends35 and 37 of the spring are connected to pins 36 and 38 respectively insuch a manner that the spring may be `subjected to compressive loadingby relative approaching movement of pins 36 and 38.

Means are provided for setting the pawls and spring 34 in either alifting or a lowering position, and this means comprises in theillustrated embodiment a setting lever 39 mounted on upraised portion 33of extension 22. In particular, upraised portion 33 is provided with anL- shaped slot having a lower portion 41 and an upper portion 42.Portion 41 of the slot slants downwardly and rearwardly, and could beconsidered forl purposes of description as approximately parallel to theaxis of spring 34 when the latter is not engaged by lever 39, asdescribed below. Upper portion 42 of the slot is substantially at rightangles to lower portion 41, and extends downwardly and forwardly towardthe spring. Lever 39 is shown in the present embodiment as being formedof a doubled or bent back metal strap, carrying a guide pin 43. Lever 39is tted over the rear edge of upraised portion 33, the shorter side 44of the lever being on the side facing the pawls, and the long side 45 onthe outside of the upper edge portion. The outer end 46 of side 45 ofthe lever is narrowed, and a spring engaging toe 47 extends laterallyfrom this narrow portion through slot 42. This toe is preferably ofsomewhat arcuate crosssection, and is slightly wider than the width ofslot portion 42, thus retaining the lever in position.

The juncture of slot portions 41 and 42 is provided with loweringpositions.

av'recess `48'which serves as a detent to retain guide pin 43`v`vhen thelever 39 is in the position shown in Figures 4 and'S. It will be notedthat' when in this position, the distance betweenpin-,43 andtoe 47 issuch that the toe exerts aftransver's'e'bending force on an intermediateportion of'spring 3,4, urging Vthe spring toward the rack bar.l

Thel lever 39`may`be moved into its lower position shown in Figures-6,V7 and 8 by'pushing the lever downwardly so that pinf 43 enters slotportion 41, the detent action of recess 448 being slight enough torelease the pin when forced downwardly. When in this position, it willbe seen that toe 47 is entirelyfree of spring 34. In order to move lever39 from its lower to its upper position, it is merely necessaryto-liftthe lever ina counterclockwise direction, upon which pin 43'lwill slideup along slot portion 41 until it snaps into place in recess 48.

VIn order to prevent the accidental entry of pin 33 in slot portions 41and 42, which would of course impair the operation of the jack, theshorter side 44 of lever 39 is provided ,with Ian extension 49 whichcovers the slot 41-42 suilicientlyl to prevent. pin 33 from entering theslot.

The operationof the jack is-best described with relation to Figures 4land y5, which show the sequential positions in raising, and Figures 6,7 and 8 which show the sequential The lever 39 is in its raised positionengaging spring 34 when it is desired to raise the jack, and' whenlowering is desired the lever is in its lower position. Basically, thedifference in raising and lowering operations stemsfrom the function ofspring 34, which when engaged by lever 39 is always under tension causedby thejtransverse bending force on its intermediate portion, but whichwhen released by lever 39 acts alternately as a tension spring and as apivoted link subject to cornpression.

In ,-the raising operation, the tension caused by thetransversevbendingforce applied to spring 3d by lever 39 is such thatboth holding pawl' 27 and lifting pawl 3l are constantly held againstthe rack bar teeth. Starting from a-positionin which the socket handleis lowered, as shown in Figure A4,y the lifting pawl 31 will engage oneof the teeth13 of the rack bar. Lowering of the handle socket, whichpivots about pin 29 when pawl 31 engages the rack bar, will causelifting of pin 25, with subsequent raising of thel housing and ofholding pau/127. When the holding pawlpasses over the apex of the nextupper tooth 13, spring 34.wi11 cause it to snap into place above theengaging surface 14 thereof. Subsequent lifting of handle socket 24, asshown in lFigure will cause the handle socket to pivot'about `pin 25,raising pin 29. Lifting pawl 3l wili thusbe'carried upwardly over theapex of the next upper tooth`13, and willjbe snapped into position abovethe surface 14-of this tooth by spring 34. lt should be noted at this"`point that the raising of handle socket 2d places spring 34 under, evengreater tension and bending stresses than existed when the handle socketwas in its iower position, and the spring is preferably so constructedthat this bending action will-not place a permanent set in the turns. Itwill be seen that repeated raising and lowering of the handle Vsocketwill therefore cause holding and lifting pawls 2,7 and 31 to advanceintermittently on the rack bar. The fact that spring 34 continuallyurges both pawls toward the rack bar prevents any accidental removal ofthe pawls from the rack bar to release the jack.

When it visvdesired to lower the jack, lever 39 is rotated into itslower position as shown in Figures 6, 7 and 8. In the position Vshown inFigure 6, the handle socket is in its lowermost position and is about tobe raised. Lifting pawl y31 is 'engaging the rack bar and holding pawl2'7 is clear of the rack bar teeth. The holding pawl has just beenpulledaway from the rack bar teeth by spring 34, which is now unstressed. Uponmoving the handle socket 'counterclockwise,` the socket will pivot aboutpivo-t pin 2 9, so that the yjackbody as welles holding pawl 27 willbelowered. 'The holdingpawljwill pass the'apex of the tooth from whichit has just been released, and the mutual Vapproach of springsupportingpins 36 and 38 will evenreleased, and will slide down this tooth untilit abuts the engaging face 14 ofthe next succeeding lower tooth. Duringthis period of engagement of pawl 27 and rack bar, spring 34 undergoescompression due to the relative approach of anchor pins 36 and 38 sothat whenlthe handle socket reaches the position shown in Figure 7, thespring is tending to push lifting pawl 31 outwardly away from the rackbar. Upon lfurther lifting of the handle socket to the position shown in'Figure 8, the holding pawl 27 will assume the load,'and lifting pawl 31will be lifted away from its tooth and will be forced away from the rackbar by spring 34. The spring is now again acting as a link, since itVis'n'either under tension nor compression, and when the handle socketis lowered from the position shown in Figure 8, lifting pawl 3l will beheld away from Y the rack bar by spring 34 until its toe 32 engages thenext lower succeeding tooth.V During this movemenn'pius 36 and 3S areagain being separated, so that by the time pawl 3l. engages its'nexttooth, spring 3d is under tension. Subsequent lowering of the handlesocket to the position shown in Figure 6, will thus release pawl Z7 fromthe rack bar and permit spring 34 to pull the holding pawl away from therack bar. The cycle will thenV be repeated.

While it will be apparent that the preferred embodiment of the inventionherein disclosed is well Vcalculatedto fulfill the objects above stated,it will be appreciated that the invention is susceptible tomodification, variation and change without departing from the properscope or fair meaning of the subjoined claims. v

What is claimed is:

l. ln a lifting jack, the combination of a bodyfmem.- ber and anactuating member pivoted to the body mem- .V ber, a holdingpawl pivotedto one of said members, a

lifting pawl pivoted to said actuating member, a vsingle coil helicalspring forming a permanent link between said pawls and energizingoperating movement of the pawls toward and away from each other, a fixedpivotal connection between one end of said spring and said holding pawl,and a fixed pivotal connection between the other end of said spring andsaid lifting pawl.

2. ln a lifting jack, a rack bar, a body member slidable thereon, anactuating member pivoted to the said body member, Va holding pawlpivoted to one of said members, a lifting pawl pivoted to said actuatingmember, a single coil helical spring forming a permanent linkbe-V tweensaid pawls and'energizing operating movement of said pawls toward'andaway from said rack bar, a fixed pivotal connection between one end ofsaid spring and said holding pawl, and a xedpivotal connection betweenthe other end of said spring andsaid lifting pawl.

3. ln a lifting jack, the combination of a body member and an actuatingmember pivoted to said body member, a holding pawl pivoted to one ofsaid members, a

' lifting pawl pivoted to said actuating member, a helical springforming a permanent link between said pawls, and a setting member'movable between a iirst position in engagement with an intermediateportion of said spring and a second position away from said spring.

4. In a lifting jack, a rack bar, a body member slidable thereon, anactuating member pivoted to said body member, a holding pawl pivoted toone of said members, a. lifting pawl pivoted to said actuating member, ahelical spring formingY a permanent link between said pawls, and asetting member movable between a first position in engagement with anintermediate portion of said spring so as to urge said pawls toward saidrack bar, and a second position away from said spring.

5. In a lifting jack, a rack bar, a body member slidable thereon, anactuating member pivoted to said body member, a holding pawl pivoted toone of said members, a lifting pawl pivoted to said actuating member, ahelical spring forming a permanent link between said pawls, and asetting member movable between a first position in engagement with anintermediate portion of said helical spring so as to urge said pawlstoward said rack bar, and a second position away from said spring, saidspring having open turns when in an unstressed condition, wherebyrelative approach of said pawls will tend to compress said spring whensaid setting member is in its second position.

6. In a lifting jack, the combination of a body member and an actuatingmember, means for pivoting said actuating member to said body member, aholding pawl pivoted to said body member, a lifting pawl pivoted to saidactuating member, a single coil helical spring forming a permanent linkbetween said pawls and energizing operating movement of the pawls towardand away from each other, a fixed pivotal connection between one end ofsaid spring and said holding pawl, and a fixed pivotal connectionbetween the other end of said spring and said lifting pawl.

7. In a lifting jack, a rack bar, a body member slidable on said rackbar, an actuating member, means for pivoting said actuating member tosaid body member, a holding pawl pivotally supported by said bodymember, a lifting pawl pivoted to said actuating member, a helicalspring forming a permanent link between said holding and lifting pawlsat points spaced from their respective pivot axes, and a setting membermovable between a jack raising position in engagement with anintermediate portion of said spring to urge said pawls toward said rackbar, and a jack-lowering position away from said spring.

8. In a lifting jack, a rack bar, a jack housing slidable thereon,rearward extensions in spaced parallel relation on said jack housing, anactuating member pivotally secured between said extensions, a holdingpawl pivoted to said body member, a lifting pawl pivoted to saidactuating member, a setting member, a helical spring forming a permanentconnection between said pawls, and a slotted portion on one of said jackbody extensions for supporting said setting member, the setting memberbeing movable in said slotted portion between a first position inengagement with an intermediate portion of said spring, and a secondposition away from said spring.

9. In a lifting jack, a rack bar, a jack housing slidable thereon,rearward extensions in spaced parallel relation on said jack housing, anactuating member pivotally secured between said extensions, a holdingpawl supported by said pivotal means, a lifting pawl pivoted to saidactuating member, a helical spring interconnecting said pawls, a settingmember, a slotted portion in one of said extensions, a pin carried bysaid setting member and extending through said slotted portion, saidsetting member being movable between a first position engaging saidspring and urging said pawls toward said rack bar, and a second positionaway from said spring, and detent means forming part of said slottedportion for retaining said setting member in its first position.

10. In a lifting jack, a rack bar, a jack housing slidable thereon,rearward extensions in spaced parallel relation on said jack housing, anactuating member pivotally secured between said extensions, a holdingpawl supported by said pivotal means, a lifting pawl pivoted to saidactuating member, a helical spring, anchor means on said pawls forsecuring said spring therebetween, at

Cil

least one of said anchor means comprising a pin, a setting member, saidsetting member being movable between a first position engaging saidspring and urging said pawls toward said rack bar, and a second positionaway from said spring, said setting member having spaced apart parallelportions tting over one of said extensions, a pin carried between saidparallel portions, a slotted portion in said one extension, said pinbeing disposed in said slotted portion, a lateral toe on one portion ofsaid setting member engageable with said spring when the setting memberis in its first position, and a guard extension on the other portion ofsaid setting member partially covering said slotted portion, wherebysaid anchor pin is prevented from entering said slotted portion.

ll. In a lifting jack, the combination of a body member and an actuatingmember having extensions in spaced parallel relation pivoted to saidbody member, a holding pawl pivoted to one `of said members, a liftingpawl pivoted to said actuating member, a helical spring interconnectingsaid pawls, a setting member, a slotted portion in one of saidextensions, a pin carried by said setting member and extending throughsaid slotted portion, said setting member being movable between a firstposition engaging said spring and urging said pawls toward said rackbar, and a second position away from said spring, and detent meansforming part of said slotted portion for retaining said setting memberin its first position by engagement with said pin.

12. In a lifting jack, a rack bar, a body member slidable thereon, anactuating member pivoted to said body member, a holding pawl pivoted tosaid body member, a lifting pawl pivoted to said actuating member, ahelical spring forming a permanent link betwen said pawls, and a settingmember movable between a first position in engagement with and exertinga transverse bending force on an intermediate portion of said spring soas to urge said pawls toward said rack bar, and a second position awayfrom said spring.

13. In a lifting jack, a rack bar, a body member slidable on said rackbar, an actuating member, means for pivoting said actuating member tosaid body member, a holding pawl pivotally supported by said bodymember, a lifting pawl pivoted on said actuating member, a helicalspring forming a permanent link between said holding and lifting pawlsat points spaced from their respective pivot axes, and a setting membermovable between a jack raising position in engagement with and exertinga transverse bending force on an intermediate portion of said spring tourge said pawls toward said rack bar, and a jack lowering position awayfrom said spring.

14. In a lifting jack, a rack bar, a body member slidable thereon, anactuating member pivoted to said body member, a holding pawl pivoted tosaid body member, a lifting pawl pivoted to said actuating member, asingle coil helical spring forming a permanent link between said pawlsand energizing operating movement of the pawls toward and away from eachother, a fixed pivotal connection between one end of said spring andsaid holding pawl, a fixed pivotal connection between the other end ofsaid spring and said lifting pawl, and a setting member movable betweena first position in engagement with an intermediate portion of saidspring and a second position away from said spring.

References Cited inthe file of this patent UNITED STATES PATE-NTS1,093,269 I-Iindman April 14, 1914 1,771,221 Johnson July 22, 19301,829,656 Johnson Oct. 27, 1931 1,839,528 Benoit Jan. 5, 1932 2,463,772Hunz Mar. 8, 1949

